Air conditioner

ABSTRACT

An air conditioner including a compressor, an outdoor heat exchanger, an expansion valve, an indoor heat exchanger, a first fan, a second fan, and a cooling/heating conversion device. The compressor is configured to compress a refrigerant and including a first compressor and a second compressor. The outdoor heat exchanger is configured to exchange heat of the refrigerant with outdoor air, and includes a first and second heat exchanger. The expansion valve is configured to expand a refrigerant. The indoor heat exchanger is configured to exchange heat of the refrigerant with indoor air. The first fan and the second fan correspond to the first heat exchanger and the second heat exchanger, respectively. The cooling/heating conversion device during a during a heating operation is connected in parallel to the first and second heat exchangers, and during a during a cooling operation is connected in series to the first and second heat exchangers.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2019-0158694 filed on Dec. 3, 2019 in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety.

BACKGROUND 1. Field

The disclosure relates to an air conditioner that is adjusted to have an optimum refrigerant passage according to an operation mode.

2. Description of the Related Art

In general, an air conditioner is an appliance which controls temperature, humidity, and air current distribution of an indoor space and also eliminates dust from air by using a refrigeration cycle in order to provide a comfortable indoor environment for users. As main components constituting the refrigeration cycle, a compressor, a condenser, an expansion device, and an evaporator are provided.

The air conditioner includes an outdoor unit and an indoor unit, and during cooling operation, heat absorbed by the indoor unit is released from the outdoor unit to lower the indoor temperature, and during heating operation, heat absorbed by the outdoor unit is released from the indoor unit to increase the indoor temperature.

The outdoor unit is provided with a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, and a fan, and the indoor unit is provided with an indoor heat exchanger.

The compressor, the four-way valve, the outdoor heat exchanger, the expansion valve, and the indoor heat exchanger are connected by a refrigerant passage to form a cooling/heating cycle.

During cooling operation, the outdoor heat exchanger may be used as a condenser that condenses a high temperature and high-pressure gas refrigerant into a liquid refrigerant, and during heating operation, the outdoor heat exchanger may be used as an evaporator that evaporates a low temperature and low-pressure liquid refrigerant.

When a plurality of outdoor heat exchangers are provided, the plurality of outdoor heat exchangers are connected in parallel regardless of the operation mode of cooling or heating, and thus the efficiency of the air conditioner may be lowered.

SUMMARY

Therefore, it is an object of the disclosure to provide an air conditioner that is varied so that a plurality of outdoor heat exchangers are connected in series or in parallel according to an operation mode to have an optimum refrigerant passage.

Additional aspects of the disclosure will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the disclosure.

According to an aspect of the disclosure, there is provided an air conditioner including: a compressor configured to compress a refrigerant and including a first compressor and a second compressor; an outdoor heat exchanger configured to have a refrigerant heat-exchanged with outdoor air, and including a first heat exchanger and a second heat exchanger; an expansion valve configured to expand a refrigerant; an indoor heat exchanger configured to have a refrigerant heat-exchanged with indoor air; a fan including a first fan and a second fan corresponding to the first heat exchanger and the second heat exchanger, respectively; and a cooling/heating conversion device controlled for the first heat exchanger and the second heat exchanger to be connected in parallel during a heating operation and controlled for the first heat exchanger and the second heat exchanger to be connected in series.

The cooling/heating conversion device may be a four-way valve, and the four-way valve may include a first four-way valve provided between the compressor, and the indoor heat exchanger and the first heat exchanger and a second four-way valve provided between the first heat exchanger and the second heat exchanger.

The first four-way valve may be controlled for the refrigerant compressed by the compressor to be moved to the indoor heat exchanger or the first heat exchanger.

The first four-way valve may be controlled for the refrigerant to be moved from the indoor heat exchanger or the first heat exchanger to the compressor.

The second four-way valve may be connected to each of the first heat exchanger, the second heat exchanger, the expansion valve, and the compressor.

During the heating operation, the refrigerant compressed by the compressor may be moved to the indoor heat exchanger through the first four-way valve and condensed through heat exchange with the indoor air, and the refrigerant condensed in the indoor exchanger may be moved to the expansion valve.

The second four-way valve may disconnect the first heat exchanger from the second heat exchanger such that the first heat exchanger and the second heat exchanger are connected in parallel.

A part of the refrigerant moved to the expansion valve and expanded may be moved to the first heat exchanger through the second four-way valve, and a remaining part of the refrigerant may be moved to the second heat exchanger and evaporated through heat exchange with outdoor air.

The refrigerant evaporated in the first heat exchanger may be moved to the compressor through the first four-way valve, and the refrigerant evaporated in the second heat exchanger may be moved to the compressor through the second four-way valve.

During the cooling operation, the second four-way valve may connect the first heat exchanger to the second heat exchanger such that the first heat exchanger and the second heat exchanger are connected in series and disconnects the expansion valve to the compressor.

The refrigerant compressed by the compressor may be moved to the first heat exchanger through the first four-way valve and condensed through heat exchange with outdoor air, and the refrigerant condensed in the first heat exchanger may be moved to the second heat exchanger through the second four-way valve and condensed through heat exchange with outdoor air.

The refrigerant condensed in the second heat exchanger may be moved to the expansion valve and expanded, the refrigerant expanded in the expansion valve may be moved to the indoor heat exchanger and evaporated through heat exchange with indoor air, and the evaporated refrigerant may be moved to the compressor through the first four-way valve.

The cooling/heating conversion device may be an on/off valve.

The first fan and the second fan may have different sizes.

The first fan and the second may have different rotation speeds.

According to another aspect of the disclosure, there is provided an air conditioner including: a compressor configured to compress a refrigerant, and provided in plural; an outdoor heat exchanger configured to have a refrigerant heat-exchanged with outdoor air and provided in plural; an expansion valve configured to expand a refrigerant; an indoor heat exchanger configured to have a refrigerant heat-exchanged with indoor air; a plurality of fans provided to correspond to the plurality of outdoor heat exchangers; and a cooling/heating conversion device controlled such that the plurality of outdoor heat exchangers are connected in parallel during a heating operation, and some of the plurality of outdoor heat exchangers are connected in series and remaining some of the plurality of outdoor heat exchangers are connected in parallel during a cooling operation.

The plurality of outdoor heat exchangers may include a first heat exchanger, a second heat exchanger, and a third heat exchanger.

The cooling/heating conversion device may be a four-way valve, and the four-way valve may include a first four-way valve provided between the compressor, and the indoor heat exchanger and the first heat exchanger and a second four-way valve provided between the first heat exchanger and the second heat exchanger, and the third heat exchanger may be connected to a refrigerant pipe that connects the first four-way valve to the second heat exchanger.

During the cooling operation, the first heat exchanger and the second heat exchanger may be connected in series, and the third heat exchanger may be connected in parallel to the first heat exchanger and the second heat exchanger.

The plurality of fans may have different sizes or rotation speeds.

Before undertaking the DETAILED DESCRIPTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term “controller” means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely.

Moreover, various functions described below can be implemented or supported by one or more computer programs, each of which is formed from computer readable program code and embodied in a computer readable medium. The terms “application” and “program” refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation in a suitable computer readable program code. The phrase “computer readable program code” includes any type of computer code, including source code, object code, and executable code. The phrase “computer readable medium” includes any type of medium capable of being accessed by a computer, such as read only memory (ROM), random access memory (RAM), a hard disk drive, a compact disc (CD), a digital video disc (DVD), or any other type of memory. A “non-transitory” computer readable medium excludes wired, wireless, optical, or other communication links that transport transitory electrical or other signals. A non-transitory computer readable medium includes media where data can be permanently stored and media where data can be stored and later overwritten, such as a rewritable optical disc or an erasable memory device.

Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts:

FIG. 1 illustrates a view of a refrigerant passage during a heating operation of an air conditioner according to an embodiment of the disclosure;

FIG. 2 illustrates a view of the refrigerant passage during a cooling operation of the air conditioner according to the embodiment of the disclosure;

FIG. 3 illustrates a view of a refrigerant passage during a heating operation of an air conditioner according to another embodiment of the disclosure, showing a state in which a second four-way valve is replaced by an on/off valve;

FIG. 4 illustrates a view of the refrigerant passage during a cooling operation of the air conditioner according to the another embodiment of the disclosure, showing a state in which a second four-way valve is replaced by an on-off valve;

FIG. 5 illustrates a view of a refrigerant passage during a heating operation of an air conditioner including three outdoor heat exchangers according to another embodiment of the disclosure; and

FIG. 6 illustrates a view illustrating the refrigerant passage during a cooling operation of the air conditioner including three outdoor heat exchangers according to the another embodiment of the disclosure.

DETAILED DESCRIPTION

FIGS. 1 through 6, discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged system or device.

Embodiments and features as described and illustrated in the disclosure are only preferred examples, and various modifications thereof may also fall within the scope of the disclosure.

Throughout the drawings, like reference numerals refer to like parts or components.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the disclosure. It is to be understood that the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. It will be further understood that the terms “include”, “comprise” and/or “have” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The terms including ordinal numbers like “first” and “second” may be used to explain various components, but the components are not limited by the terms. The terms are only for the purpose of distinguishing a component from another. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the disclosure. Descriptions shall be understood as to include any and all combinations of one or more of the associated listed items when the items are described by using the conjunctive term “˜and/or˜,” or the like.

The terms “front”, “rear”, “upper”, “lower”, “top”, and “bottom” as herein used are defined with respect to the drawings, but the terms may not restrict the shape and position of the respective components.

Hereinafter, embodiments of the disclosure will be described in detail with reference to the accompanying drawings.

In FIGS. 1 to 6, a broken line indicates a refrigerant passage through which a high-pressure refrigerant flows, and a solid line indicates a refrigerant passage through which a low-pressure refrigerant flows.

FIG. 1 illustrates a view of a refrigerant passage during a heating operation of an air conditioner according to an embodiment of the disclosure.

Referring to FIG. 1, an air conditioner may include a compressor 10 compressing a refrigerant, an outdoor heat exchanger 20 allowing a refrigerant to have heat exchanged with outdoor air, an expansion valve 30 expanding a refrigerant, an indoor heat exchanger 40 allowing a refrigerant to have heat exchanged with indoor air, a fan 50 guiding air to the outdoor heat exchanger 20, and a cooling/heating conversion devices 60 or 70 performing conversion of heating and cooling.

The compressor 10 may compress a refrigerant, and include a first compressor 11 and a second compressor 13. The first compressor 11 and the second compressor 13 may be connected in parallel to each other.

The outdoor heat exchanger 20 may allow a refrigerant to have heat exchanged with outdoor air. During a heating operation of the air conditioner, the outdoor heat exchanger 20 may be used as an evaporator. In this case, the indoor heat exchanger 40 may be used as a condenser. During a cooling operation of the air conditioner, the outdoor heat exchanger 20 may be used as a condenser. In this case, the indoor heat exchanger 40 may be used as an evaporator.

The outdoor heat exchanger 20 may be provided in plural. The outdoor heat exchanger 20 may include a first heat exchanger 21 and a second heat exchanger 23.

The indoor heat exchanger 40 may allow a refrigerant to have heat exchanged with indoor air. During a heating operation of the air conditioner, the indoor heat exchanger 40 may be used as a condenser. In this case, the outdoor heat exchanger 20 may be used as an evaporator. During a cooling operation of the air conditioner, the indoor heat exchanger 40 may be used as an evaporator. In this case, the outdoor heat exchanger 20 may be used as a condenser.

The fan 50 may be provided to correspond to the outdoor heat exchanger 20 to guide air to the outdoor heat exchanger 20. The fan 50 may include a first fan 51 provided to correspond to the first heat exchanger 21 and a second fan 53 provided to correspond to the second heat exchanger 23.

The cooling/heating conversion device 60 may perform conversion of heating and cooling of the air conditioner. The cooling/heating conversion device 60 may be controlled such that the first heat exchanger 21 and the second heat exchanger 23 are connected in parallel during the heating operation of the air conditioner. In addition, the cooling/heating conversion device 60 may be controlled such that the first heat exchanger 21 and the second heat exchanger 23 are connected in series during the cooling operation of the air conditioner. Details thereof will be described below.

The cooling/heating conversion device 60 may be provided as a four-way valve 60. The four-way valve 60 includes a first four-way valve 61 provided between the compressor 10 and the indoor heat exchanger 40 and the first heat exchanger 21 and a second four-way valve 63 provided between the first heat exchanger 21 and the second heat exchanger 23.

The first four-way valve 61 may be provided between a first refrigerant passage P1 and a second refrigerant passage P2. In addition, the first four-way valve 61 may be provided between an eighth refrigerant passage P8 and a ninth refrigerant passage P9. That is, the first four-way valve 61 may be provided to be connected to the first refrigerant passage P1, the second refrigerant passage P2, the eighth refrigerant passage P8, and the ninth refrigerant passage P9.

The refrigerant passage may include a first refrigerant passage P1 connecting the compressor 10 to the first four-way valve 61, a second refrigerant passage P2 connecting the first four-way valve 61 to the indoor heat exchanger 40, a third refrigerant passage P3 connecting the indoor heat exchanger 40 to the expansion valve 30, a fourth refrigerant passage P4 connecting the expansion valve 30 to the second heat exchanger 23, a fifth refrigerant passage P5 connecting the expansion valve 30 to the second four-way valve 63, a sixth refrigerant passage P6 connecting the second heat exchanger 23 to the second four-way valve 63, a seventh refrigerant passage P7 connecting the second four-way valve 63 to the first heat exchanger 21, an eight refrigerant passage P8 connecting the first heat exchanger 21 to the first four-way valve 61, a ninth refrigerant passage P9 connecting the first four-way valve 61 to the compressor 10, and a tenth refrigerant passage P10 connecting the second four-way valve 63 to the compressor 10.

The second four-way valve 63 may be provided between the sixth refrigerant passage P6 and the seventh refrigerant passage P7. In addition, the second four-way valve 63 may be provided between the fifth refrigerant passage P5 and the tenth refrigerant passage P10. That is, the second four-way valve 63 may be provided to be connected to the sixth refrigerant passage P6, the seventh refrigerant passage P7, the fifth refrigerant passage P5, and the tenth refrigerant passage P10.

During a heating operation of the air conditioner, a refrigerant compressed by the compressor 10 may be moved to the indoor heat exchanger 40 through the first refrigerant passage P1 and the second refrigerant passage P2. In this case, the first four-way valve 61 blocks the eighth refrigerant passage P8 and the ninth refrigerant passage P9 such that the refrigerant flows through the first refrigerant passage P1 and the second refrigerant passage P2 sequentially to the indoor heat exchanger 40.

Since the indoor heat exchanger 40 is used as a condenser during the heating operation of the air conditioner, a high-temperature and high-pressure refrigerant compressed by the compressor 10 may have heat exchanged with indoor air to heat the indoor air. The refrigerant compressed by the compressor 10 is a high-temperature and high-pressure gas refrigerant, which may be easily liquefiable. The high-temperature and high-pressure gas refrigerant compressed in the compressor 10 may have heat exchanged with indoor air in the indoor heat exchanger 40 while releasing heat to the indoor air to be liquefied into a low-temperature and high-pressure liquid refrigerant. The indoor air may be warmed by the heat released.

The low temperature and high-pressure liquid refrigerant condensed in the indoor heat exchanger 40 may be moved to the expansion valve 30 through the third refrigerant passage P3. The low-temperature and high-pressure liquid refrigerant may be expanded in the expansion valve 30 to become a low-temperature and low-pressure liquid refrigerant, which may be easily evaporable.

A part of the low-temperature and low-pressure liquid refrigerant expanded by the expansion valve 30 may be moved to the second heat exchanger 23 through the fourth refrigerant passage P4. In this case, the refrigerant flowing into the second heat exchanger 23 may be in a state in which a low-temperature and low-pressure gas refrigerant and a low-temperature and low-pressure liquid refrigerant are mixed. Since the outdoor heat exchanger 20 is used as an evaporator during the heating operation of the air conditioner, the low-temperature and low-pressure liquid refrigerant moved to the second heat exchanger 23 have heat exchanged with outdoor air to absorb heat from the outdoor air. The low temperature and low-pressure liquid refrigerant may absorb heat and become a high temperature and low-pressure gas refrigerant. The high-temperature and low-pressure gas refrigerant evaporated in the second heat exchanger 23 may be introduced into the compressor 10 through the sixth refrigerant passage P6 and the tenth refrigerant passage P10. In this case, the second four-way valve 63 may be controlled such that the high-temperature and low-pressure gas refrigerant moved to the sixth refrigerant passage P6 is moved to the compressor 10 through the tenth refrigerant passage P10. The high-temperature and low-pressure gas refrigerant may be compressed and become a high temperature and high-pressure gas refrigerant.

A remaining part of the low-temperature and low-pressure liquid refrigerant expanded by the expansion valve 30 may be moved to the first heat exchanger 21 through the fifth refrigerant passage P5 and the seventh refrigerant passage P7. In this case, the refrigerant flowing into the first heat exchanger 21 may be in a state in which a low-temperature and low-pressure gas refrigerant and a low-temperature and low-pressure liquid refrigerant are mixed. In this case, the second four-way valve 63 may be controlled such that the low-temperature and low-pressure liquid refrigerant moved to the fifth refrigerant passage P6 is moved to the first heat exchanger 21 through the seventh refrigerant passage P7. Since the outdoor heat exchanger 20 is used as an evaporator during a heating operation of the air conditioner, the low temperature and low-pressure liquid refrigerant moved to the first heat exchanger 21 may have heat exchanged with the outdoor air to absorb heat from the outdoor air. The low temperature and low-pressure liquid refrigerant may absorb the heat and become a high temperature and low-pressure gas refrigerant. The high-temperature and low-pressure gas refrigerant evaporated in the first heat exchanger 21 may be introduced into the compressor 10 through the eighth refrigerant passage P8 and the ninth refrigerant passage P9. The high temperature and low-pressure gas refrigerant introduced into the compressor 10 may be compressed to become a high temperature and high-pressure gas refrigerant.

As described above, during a heating operation of the air conditioner, the second four-way valve 63 may allow the first heat exchanger 21 and the second heat exchanger 23 to be connected in parallel.

The outdoor heat exchanger 20 is used as an evaporator during the heating operation of the air conditioner, and a decrease in system low-pressure due to a pressure drop of the refrigerant during evaporation in the first heat exchanger 21 and the second heat exchanger 23 may cause the system performance and efficiency to be degraded. In addition, with regard to defrost condition, a decrease in refrigerant temperature due to a pressure drop of the refrigerant may promote defrost, thereby causing the system performance and efficiency to be degraded.

In order to prevent the performance and efficiency of the system from deteriorating as described above, when the first heat exchanger 21 and the second heat exchanger 23 are connected in parallel so that a shorter refrigerant passage may be achieved, thereby reducing the pressure drop of the refrigerant. When the pressure drop of the refrigerant is reduced, the system low-pressure is increased and the defrost is delayed, so that the overall system efficiency may be improved. In a case where the outdoor heat exchanger 20 is used as an evaporator, an optimum heat exchange efficiency may be provided when the refrigerant passage has a length of 6 m to 8 m. That is, during a heating operation, in the evaporation process in the outdoor heat exchanger 20, the refrigerant converted to a gas refrigerant is subject to flow rate increase. When the length of the refrigerant passage is shortened, the flow rate of the refrigerant is reduced, thereby improving the heat exchange efficiency. Reducing the flow rate of the refrigerant may prevent a pressure drop in the evaporation, thereby increasing the system low-pressure and improving the overall system efficiency.

In a case where the outdoor heat exchanger 20 is used as a condenser, the optimal heat exchange efficiency may be provided when the refrigerant passage has a length of about 15 m to 20 m. That is, during a cooling operation, in the condensation process in the outdoor heat exchanger 20, the refrigerant converted to a liquid state is subject to flow rate decrease. When the length of the refrigerant passage is lengthened, the flow rate of the refrigerant is increased, thereby improving the heat exchange efficiency.

In other words, in a heating operation in which the outdoor heat exchanger 20 is used as an evaporator, the length of the refrigerant passage needs to be shortened to improve the heat exchange efficiency. In a cooling operation in which the outdoor heat exchanger 20 is used as a condenser, the length of the refrigerant passage needs to be increased to improve the heat exchange efficiency. Accordingly, in a cooling operation in which the first heat exchanger 21 and the second heat exchanger 23 are connected in series, the length of the refrigerant passage may be limited to 5 m to 30 m in consideration of the size of the outdoor unit. In a heating operation in which the first heat exchanger 21 and the second heat exchanger 23 are connected in parallel, the length of the refrigerant passage may be provided one third to two third of the length of the refrigerant passage when the first heat exchanger 21 and the second heat exchanger 23 are connected in series.

In addition, the system efficiency may be improved by reducing the rotation speeds of the first fan 51 and the second fan 53 provided at the rear ends of the refrigerant passages of the first heat exchanger 21 and the second heat exchanger 23 connected in parallel according to the operating load to lower the consumption input. In addition, when the sizes of the first heat exchanger 21 and the second heat exchanger 23 are different, the rotational speed reductions of the first fan 51 and the second fan 53 may be set to be different from each other to secure the optimal system efficiency. In addition, when the sizes of the first heat exchanger 21 and the second heat exchanger 23 are different, the sizes of the first fan 51 and the second fan 53 may be provided to be different from each other to correspond to the sizes of the first heat exchanger 21 and the second heat exchanger to lower the consumption input, so that the efficiency may be improved.

FIG. 2 illustrates a view of the refrigerant passage during a cooling operation of the air conditioner according to the embodiment of the disclosure.

Referring to FIG. 2, a refrigerant compressed in the compressor 10 during a cooling operation of the air conditioner may be moved to the first heat exchanger 21 through the first refrigerant passage P1 and the eighth refrigerant passage P8. In this case, the first four-way valve 61 may block the second refrigerant passage P2 and the ninth refrigerant passage P9 such that the refrigerant may be moved to the first heat exchanger 21 through the first refrigerant passage P1 and the eighth refrigerant passage P8.

Since the outdoor heat exchanger 20 is used as a condenser during the cooling operation of the air conditioner, the high temperature and high-pressure refrigerant compressed by the compressor 10 may have heat exchanged with outdoor air to release heat to the outdoor air. The refrigerant compressed by the compressor 10 is a high-temperature and high-pressure gas refrigerant, which may be easily liquefiable. The high-temperature and high-pressure gas refrigerant compressed in the compressor 10 may have heat exchanged with outdoor air in the first heat exchanger 21 while releasing heat to the outdoor air to be liquefied into a low-temperature and high-pressure liquid refrigerant.

The refrigerant condensed in the first heat exchanger 21 may be moved to the second heat exchanger 23 through the seventh refrigerant passage P7 and the sixth refrigerant passage P6. The refrigerant moved to the second heat exchanger 23 may have heat exchanged with outdoor air to release heat to the outdoor air. Accordingly, the refrigerant passed through the second heat exchanger 23 may be a low-temperature and high-pressure liquid refrigerant having a temperature lower than that of the refrigerant passed through the first heat exchanger 21.

As described above, during the cooling operation of the air conditioner, the second four-way valve 63 may allow the first heat exchanger 21 and the second heat exchanger 23 to be connected in series.

In the cooling operation of the air conditioner, the outdoor heat exchanger 20 is used as a condenser, and a high-temperature and high-pressure gas refrigerant is introduced into the outdoor heat exchanger 20, so that the refrigerant in the process of being condensed in the outdoor heat exchanger 20 may be subject to flow rate decrease. Accordingly, when the length of the refrigerant passage is increased by connecting the first heat exchanger 21 and the second heat exchanger 23 in series, the heat exchange efficiency and overall system efficiency may be improved. In addition, when the rotational speed of the second fan 53 corresponding to the second heat exchanger 23 between the first fan 51 and the second fan 53 provided at the rear ends of the refrigerant passages of the first heat exchanger 21 and the second heat exchanger 23 connected in series according to the operating load is reduced, the consumption input may be lowered, thereby improving the system efficiency. This may be achieved because the first fan 51 and the second fan 53 are provided to correspond to the first heat exchanger 21 and the second heat exchanger 23, respectively.

The low temperature and high-pressure liquid refrigerant condensed in the first heat exchanger 21 and the second heat exchanger 23 may be moved to the expansion valve 30 through the fourth refrigerant passage P4. The low-temperature and high-pressure liquid refrigerant may be expanded in the expansion valve 30 to become a low-temperature and low-pressure liquid refrigerant, which may be easily evaporated.

The low-temperature and low-pressure liquid refrigerant expanded by the expansion valve 30 may be moved to the indoor heat exchanger 40 through the third refrigerant passage P3. Since the indoor heat exchanger 40 is used as an evaporator during the cooling operation of the air conditioner, the low temperature and low-pressure liquid refrigerant introduced into the indoor heat exchanger 40 may have heat exchanged with the indoor air to absorb heat from the indoor air. The low temperature and low-pressure liquid refrigerant may absorb heat and become a high temperature and low-pressure gas refrigerant. Accordingly, the indoor air may be cooled. The high-temperature and low-pressure gas refrigerant evaporated in the indoor heat exchanger 40 may flow into the compressor 10 through the second refrigerant passage P2 and the ninth refrigerant passage P9.

FIG. 3 illustrates a view of a refrigerant passage during a heating operation of an air conditioner according to another embodiment of the disclosure, showing a state in which a second four-way valve is replaced by an on-off valve.

Referring to FIG. 3, a cooling/heating conversion device 60 may be provided as an on-off valve. That is, a plurality of on-off valves 71, 73, and 75 may be used instead of the second four-way valve 63 shown in FIG. 1.

The on-off valve 70 may include a first on-off valve 71 provided between the sixth refrigerant passage P6 and the seventh refrigerant passage P7, a second on-off valve 73 provided in the fifth refrigerant passage P5, and a third on-off valve 75 provided in the tenth refrigerant passage P10. Components other than the on-off valve 70 are the same as those shown in FIG. 1, and thus descriptions thereof will be omitted.

Only parts related to the on-off valve 70 during the heating operation of the air conditioner will be described. A part of the low-temperature and low-pressure liquid refrigerant expanded in the expansion valve 30 may be moved to the second heat exchanger 23 through the fourth refrigerant passage P4. In this case, the refrigerant flowing into the second heat exchanger 23 may be in a state in which a low-temperature and low-pressure gas refrigerant and a low-temperature and low-pressure liquid refrigerant are mixed. Since the outdoor heat exchanger 20 is used as an evaporator during the heating operation of the air conditioner, the low-temperature and low-pressure liquid refrigerant moved to the second heat exchanger 23 may have heat exchanged with outdoor air to absorb heat from the outdoor air. The low temperature and low-pressure liquid refrigerant may absorb heat and become a high temperature and low-pressure gas refrigerant. The high-temperature and low-pressure gas refrigerant evaporated in the second heat exchanger 23 may be introduced into the compressor 10 through the sixth refrigerant passage P6 and the tenth refrigerant passage P10. In this case, the first on-off valve 71 may be controlled to be closed and the third on-off valve 75 may be controlled to be opened. The high temperature and low-pressure gas refrigerant introduced into the compressor 10 may be compressed to become a high temperature and high-pressure gas refrigerant.

A remaining part of the low-temperature and low-pressure liquid refrigerant expanded by the expansion valve 30 may be moved to the first heat exchanger 21 through the fifth refrigerant passage P5 and the seventh refrigerant passage P7. In this case, the refrigerant flowing into the first heat exchanger 21 may be in a state in which a low-temperature and low-pressure gas refrigerant and a low-temperature and low-pressure liquid refrigerant are mixed. In this case, the first on-off valve 71 may be controlled to be closed and the second on-off valve 73 may be controlled to be opened. Since the outdoor heat exchanger 20 is used as an evaporator during the heating operation of the air conditioner, the low temperature and low-pressure liquid refrigerant moved to the first heat exchanger 21 may have heat exchanged with the outdoor air to absorb heat from the outdoor air. The low temperature and low-pressure liquid refrigerant absorbs heat and become a high-temperature and low-pressure gas refrigerant. The high-temperature and low-pressure gas refrigerant evaporated in the first heat exchanger 21 may be introduced into the compressor 10 through the eighth refrigerant passage P8 and the ninth refrigerant passage P9. The high-temperature and low-pressure gas refrigerant introduced into the compressor 10 may be compressed to become a high temperature and high-pressure gas refrigerant.

That is, when the on-off valve 70 is used as the cooling/heating conversion device, the first on-off valve 71 may be controlled to be closed during the heating operation of the air conditioner, and the second on-off valve 73 and the third on-off valve 75 may be controlled to be opened.

FIG. 4 illustrates a view of the refrigerant passage during a cooling operation of the air conditioner according to the another embodiment of the disclosure, showing a state in which a second four-way valve is replaced by an on-off valve.

Referring to FIG. 4, the cooling/heating conversion device 60 may be provided as an on-off valve. That is, instead of the second four-way valve 63 shown in FIG. 2, a plurality of on-off valves 71, 73, and 75 may be used.

The on-off valve 70 may include a first on-off valve 71 provided between the sixth refrigerant passage P6 and the seventh refrigerant passage P7, a second on-off valve 73 provided in the fifth refrigerant passage P5, and a third on-off valve 75 provided in the tenth refrigerant passage P10. Components other than the on-off valve 70 are the same as those shown in FIG. 2, and thus descriptions thereof will be omitted.

Only parts related to the on-off valve 70 during the cooling operation of the air conditioner will be described. Since the outdoor heat exchanger 20 is used as a condenser during the cooling operation of the air conditioner, a high temperature and high-pressure refrigerant compressed by the compressor 10 may have heat exchanged with outdoor air to release heat to the outdoor air. The refrigerant compressed by the compressor 10 is a high-temperature and high-pressure gas refrigerant, which may be easily liquefiable. The high-temperature and high-pressure gas refrigerant compressed by the compressor 10 may have heat exchanged with outdoor air in the first heat exchanger 21 while releasing heat to the outdoor air to be liquefied into a low-temperature and high-pressure liquid refrigerant.

The refrigerant condensed in the first heat exchanger 21 may be moved to the second heat exchanger 23 through the seventh refrigerant passage P7 and the sixth refrigerant passage P6. In this case, the first on-off valve 71 may be controlled to be opened, and the second on-off valve 73 and the third on-off valve 75 may be controlled to be closed. The refrigerant moved to the second heat exchanger 23 may have heat exchanged with outdoor air to release heat to the outdoor air. Accordingly, the refrigerant passed through the second heat exchanger 23 may be a low-temperature and high-pressure liquid refrigerant having a temperature lower than that of the refrigerant passed through the first heat exchanger 21.

FIG. 5 illustrates a view of a refrigerant passage during a heating operation of an air conditioner including three outdoor heat exchangers according to another embodiment of the disclosure.

Referring to FIG. 5, an outdoor heat exchanger 20 may include a first heat exchanger 21, a second heat exchanger 23, and a third heat exchanger 25. The first heat exchanger 21, the second heat exchanger 23, and the third heat exchanger 25 may be provided with a first fan 51, a second fan 53, and a third fan 55 corresponding thereto.

Compared with the configuration shown in FIG. 1, when the outdoor heat exchanger 20 is provided to include the first heat exchanger 21, the second heat exchanger 23 during a heating operation of the air conditioner, and the third heat exchanger 25, the first heat exchanger 21, the second heat exchanger 23, and the third heat exchanger 25 may be connected in parallel.

That is, a part of the refrigerant expanded in the expansion valve 30 may flow into the third heat exchanger 25 through an eleventh refrigerant passage P11 and evaporate, and may be moved to the eighth refrigerant passage P8 through a twelfth refrigerant passage P12. The refrigerant moved to the eighth refrigerant passage P8 may flow into the compressor 10 through a ninth refrigerant passage P9.

In addition, a part of the refrigerant expanded in the expansion valve 30 may flow into the second heat exchanger 23 through a fourth refrigerant passage P4 and evaporates, and may flow into the compressor 10 through a sixth refrigerant passage P6 and a tenth refrigerant passage P10.

In addition, a remaining part of the refrigerant expanded in the expansion valve 30 may flow into the first heat exchanger 21 through a fifth refrigerant passage P5 and a seventh refrigerant passage P7 and evaporates, and may flow into the compressor 10 through the eighth refrigerant passage P8 and the ninth refrigerant passage P9.

FIG. 6 illustrates a view of the refrigerant passage during a cooling operation of the air conditioner including three outdoor heat exchangers according to the another embodiment of the disclosure.

Referring to FIG. 6, the outdoor heat exchanger 20 may include the first heat exchanger 21, the second heat exchanger 23, and the third heat exchanger 25. The first heat exchanger 21, the second heat exchanger 23 and the third heat exchanger 25 may be provided with the first fan 51, the second fan 53, and the third fan 55 corresponding thereto. The first fan 51, the second fan 53, and the third fan 55 may have different sizes or different rotational speeds, similar to the first fan 51 and the second fan 53 illustrated in FIG. 2.

Compared with the configuration shown in FIG. 2, when the outdoor heat exchanger 20 is provided to include the first heat exchanger 21, the second heat exchanger 23, and the third heat exchanger 25 during a cooling operation of the air conditioner, the first heat exchanger 21 and the second heat exchanger 23 may be connected in series, and the third heat exchanger 25 may be connected in parallel to the first heat exchanger 21 and the second heat exchanger 23.

That is, a part of the refrigerant compressed by the compressor 10 may flow into the first heat exchanger 21 through the first refrigerant passage P1 and the eighth refrigerant passage P8. In addition, the refrigerant condensed in the first heat exchanger 21 may flow into the second heat exchanger 23 through the seventh refrigerant passage P7 and the sixth refrigerant passage P6. The refrigerant condensed in the second heat exchanger 23 may be introduced into the expansion valve 30 through the fourth refrigerant passage P4.

In addition, a remaining part of the refrigerant compressed by the compressor 10 may flow into the third heat exchanger 25 through the first refrigerant passage P1, the eighth refrigerant passage P8, and the twelfth refrigerant passage P12. The refrigerant condensed in the third heat exchanger 25 may be introduced into the expansion valve 30 through the eleventh refrigerant passage P11.

As is apparent from the above, according to the embodiments of the disclosure, a plurality of outdoor heat exchangers are varied to be connected in series or in parallel according to an operation mode, so that the heat exchange efficiency can be enhanced.

Although the present disclosure has been described with various embodiments, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims. 

What is claimed is:
 1. An air conditioner comprising: a compressor configured to compress a refrigerant, wherein the compressor includes a first compressor and a second compressor; an outdoor heat exchanger configured to exchange heat of the refrigerant with outdoor air, wherein the outdoor heat exchanger includes a first heat exchanger and a second heat exchanger; an expansion valve configured to expand the refrigerant; an indoor heat exchanger configured to include exchange heat of the refrigerant with indoor air; a fan including a first fan and a second fan corresponding to the first heat exchanger and the second heat exchanger, respectively; and a cooling/heating conversion device, wherein during a heating operation the cooling/heating conversion device is connected in parallel to the first heat exchanger and the second heat exchanger and during a cooling operation, the cooling/heating conversion device is connected in series to the first heat exchanger and the second heat exchanger.
 2. The air conditioner of claim 1, wherein the cooling/heating conversion device is a four-way valve, and the four-way valve includes a first four-way valve provided between the compressor, and the indoor heat exchanger and the first heat exchanger and a second four-way valve provided between the first heat exchanger and the second heat exchanger.
 3. The air conditioner of claim 2, wherein the first four-way valve is configured to move the refrigerant compressed by the compressor to the indoor heat exchanger or the first heat exchanger.
 4. The air conditioner of claim 3, wherein the first four-way valve configured to move the refrigerant from the indoor heat exchanger or the first heat exchanger to the compressor.
 5. The air conditioner of claim 4, wherein the second four-way valve is connected to each of the first heat exchanger, the second heat exchanger, the expansion valve, and the compressor.
 6. The air conditioner of claim 5, wherein during the heating operation, the refrigerant compressed by the compressor is moved to the indoor heat exchanger through the first four-way valve and condensed by exchanging heat with the indoor air, and the refrigerant condensed in the indoor heat exchanger is moved to the expansion valve.
 7. The air conditioner of claim 6, wherein the second four-way valve is configured to disconnect the first heat exchanger from the second heat exchanger such that the first heat exchanger and the second heat exchanger are connected in parallel.
 8. The air conditioner of claim 7, wherein: a part of the refrigerant is moved to the expansion valve and expanded is moved to the first heat exchanger through the second four-way valve, and a remaining part of the refrigerant is moved to the second heat exchanger and evaporated by exchanging heat with the outdoor air.
 9. The air conditioner of claim 8, wherein: the refrigerant evaporated in the first heat exchanger is moved to the compressor through the first four-way valve, and the refrigerant evaporated in the second heat exchanger is moved to the compressor through the second four-way valve.
 10. The air conditioner of claim 5, wherein during the cooling operation, the second four-way valve is configured to connect the first heat exchanger to the second heat exchanger such that the first heat exchanger and the second heat exchanger are connected in series and disconnects the expansion valve to the compressor.
 11. The air conditioner of claim 10, wherein: the refrigerant compressed by the compressor is moved to the first heat exchanger through the first four-way valve and condensed by exchanging heat with the outdoor air, and the refrigerant condensed in the first heat exchanger is moved to the second heat exchanger through the second four-way valve and condensed by exchanging heat with the outdoor air.
 12. The air conditioner of claim 11, wherein: the refrigerant condensed in the second heat exchanger is moved to the expansion valve and expanded, the refrigerant expanded in the expansion valve is moved to the indoor heat exchanger and evaporated by exchanging heat with the indoor air, and the evaporated refrigerant is moved to the compressor through the first four-way valve.
 13. The air conditioner of claim 1, wherein the cooling/heating conversion device is an on/off valve.
 14. The air conditioner of claim 1, wherein the first fan and the second fan are different sizes.
 15. The air conditioner of claim 1, wherein the first fan and the second fan include different rotation speeds.
 16. An air conditioner comprising: a plurality of compressors configured to compress a refrigerant; a plurality of outdoor heat exchangers configured to exchange heat of the refrigerant with outdoor air; an expansion valve configured to expand the refrigerant; an indoor heat exchanger configured to exchange heat of the refrigerant with indoor air; a plurality of fans provided to correspond to the plurality of outdoor heat exchangers; and a cooling/heating conversion device, wherein during a heating operation the plurality of outdoor heat exchangers are connected in parallel, and during a cooling operation a portion of the plurality of outdoor heat exchangers are connected in series and a remaining portion of the plurality of outdoor heat exchangers are connected in parallel.
 17. The air conditioner of claim 16, wherein the plurality of outdoor heat exchangers include a first heat exchanger, a second heat exchanger, and a third heat exchanger.
 18. The air conditioner of claim 17, wherein the cooling/heating conversion device is a four-way valve, and the four-way valve includes a first four-way valve provided between a compressor of the plurality of compressors, and the indoor heat exchanger and the first heat exchanger and a second four-way valve provided between the first heat exchanger and the second heat exchanger, and the third heat exchanger is connected to a refrigerant pipe that connects the first four-way valve to the second heat exchanger.
 19. The air conditioner of claim 18, wherein during the cooling operation, the first heat exchanger and the second heat exchanger are connected in series, and the third heat exchanger is connected in parallel to the first heat exchanger and the second heat exchanger.
 20. The air conditioner of claim 16, wherein the plurality of fans include different sizes or rotation speeds. 